Reproductive hormones Flashcards
(13 cards)
reproductive system
The gonads are separate in males and females and are the primary source of sex hormones
Steroid hormones produced include androgens, estrogen, and progestin
Male reproductive system
The synthesis and secretion of the male sex hormones is controlled by luteinizing hormone
The male sex hormones, androgens, control the development of the male reproductive system
testosterone
Testosterone (and FSH) stimulates spermatogenesis
Testosterone affect the development of the male secondary sex characteristics
Development of facial and body hair
Growth of larynx
Strengthening of muscles
Increases the secretion of body oils
Testosterone stimulates the maturation of the sex organs
production of sperm and male sex hormones
The follicle-stimulating hormone (FSH) stimulates the production of sperm cells in the Sertoli cells of the seminiferous tubules
Testosterone increases sperm production
puberty in males
The hypothalamus secretes the gonadotropin-releasing hormone (GnRH)
GnRH activates the pituitary gland to secrete and release FSH and LH
Follicle-stimulating hormone (FSH)
stimulates the production of sperm cells in the Sertoli cells of the seminiferous tubules
Luteinizing hormone (LH)
promotes the production of testosterone by the interstitial cells
feedback –> male sex hormones
Hypothalamus secretes GnRH–>pituitary gland
Pituitary gland secretes FSH and LH–>testes
FSH –> Sertoli cells –> spermatogenesis
LH–> Leydig cells –> testosterone
Testosterone –>GnRH and LH
Testosterone –> Sertoli cells –> inhibin –> FSH
female reproductive system
The synthesis and secretion of the female sex hormones is controlled by follicle-stimulating hormone
The female sex hormones, estrogen, control the development of the female reproductive system
The female sex hormones, progestin, prepares and maintains the uterus for childrearing
Estradiol (and FSH) stimulates oogenesis
Estradiol affect the development of the female secondary sex characteristics
Breast development
Growth of body hair
Widening of pelvis
Estradiol stimulates the maturation of the sex organs
ovaries and egg development
Follicles are fluid-filled sacs that contain an immature oocyte
Females are born with ~1 million follicles in each ovary
Each ovary contains ~400,000 follicles at puberty
Between puberty and menopause ~400 ova will mature and be ovulated
egg development
GnRH in the hypothalamus –> anterior pituitary gland
FSH by anterior pituitary gland –> ovaries
Many follicles start to develop during each monthly reproductive cycle but usually only one follicle becomes dominant and reaches maturity
feedback loops –> women
- As estrogen levels rise, a negative feedback message is sent to the pituitary gland to turn off secretions of FSH
- As estrogen levels rise, a positive feedback message is sent to the pituitary gland to turn on secretions of LH
LH causes ovulation
ovulation
Follicle bursts and releases the ovum
The released ovum is pulled through the fallopian tubes
The follicle becomes a corpus luteum and secretes progesterone and estrogen
develops the endometrium
Hormones estrogen and progesterone diminish the signal for FSH and LH secretion
menstruation
If the ovum is not fertilized, the drop in GnRH (and FSH and LH) will signal the deterioration of the corpus luteum
Levels of estrogen and progesterone will drop and signal the beginning of menstruation
The developed uterine lining is no longer needed and is released
fertilization
Fertilization can only occur during the ovum’s passage through the fallopian tubes
Occurs when sperm penetrates the follicle and into the ovum
The first cell, zygote, undergoes mitotic divisions to become an embryo
Implantation occurs in the uterine lining
